Control of the saline content of boiler waters



April18, 1933. H. KRIEGSHEIM 1,904,900

CONTROL OF THE SALINE CONTENT OF BOILER WATERS Original Filed March 8,1927 Patented Apr. 18, 1933 UNITED STATES PATENT OFFICE HEINRICHKBIEGSHEIM, OF NEW YORK, N. Y., ASSIGNOR TO THE PERMUTIT COMPANY OF NEWYORK, N. Y., A CORPORATION OF DELAWARE CONTROL OF THE SALINE CONTENT OFBOILER WATERS Continuation ofapplieation Serial No. 173,781, filed March8, 1927. This application filed November 11,

This invention relates to control of the,

salinev content of boiler waters; and it com prises a method ofmaintaining a concentration of dissolved salines below a desired max- 5imum in operating steam boilers wherein the boiler salines aredischarged from the boiler under pressure at substantially constantrates irrespective of pressure variation within the boiler and overextended periods of time, without coordination of the rate of dischargewith varying rates of feeding water tothe boiler in the course of suchperiods, the discharged boiler salines being normally cooled,advantageously by transfer of heat to the feed water, and the pressurebeing then reduced to atmospheric, the discharge of salines beingcontrolled by adjusting their flow after the release of pressureat'fixed rates directly proportioned to observed variation in theconcentration of the boiler salines dis-* charged; and it furthercomprises a new assemblage of apparatus elements useful in applying thedescribed method, said assemblage comprising a boiler, a water dischargeline therefrom usually including a heat interchanger, a control tankopen to the atmosphere and'receiving the salines from the dischargeline, a valve in the discharge line, a

float in the control tank controlling the dis- :3 charge valve and anadjustable outlet for the control tank adapted with the float control ofthe valve to maintain substantially constant an adjusted rate of.discharge by the discharge line; all as more fully hereinafter set forthand as claimed.

In the modern steam power station usually the greater part of the waterevaporated to steam in the boiler is condensed for return thereto. Thecondensate returned mayflconstitute as much as 95 per cent of the feedwater put into the boiler, the loss of steam due to leakage etc. inpassing from the boilers through the engines to the condensers amountingto perhaps *5 per cent. This loss is made up by water from an outsidesource. The make-up water may be raw water or softened water ordistilled water produced in a separate evaporator. Y

It has been assumed that by distilling the make-up water, the problem ofavoiding un- Serial No. 574,442.

desirable concentrations of salts in the boiler water and the formationof scale in the boilers would be solved. However, the unavoidablecondenser leakage in condensing exhaust steam and the fact that evendistilled water as commercially produced on a large scale is neverentirely free of dissolved salts, prevents the accomplishment of thedesired result. There is always some saline matter in the boiler feedwater. The water leaking into the condenser as well as the make-upwater, irrespective of its source, always contains a certain amount ofmineral matter or salts in solution. In plants operating without the useof condensers, or where steam is used for various purposes other thanfor power and in those where only a part of the produced steam can bereturned as condensate, the proportion of make-up water is, of course,increased, and, in fact, may reach 100 per cent .of the total steamproduction and thus of the feed water. As the amount of salts introducedinto the boiler by the feed water during a day is usually substantiallyconstant for an particular installation, the-quantity of .soli s addedto the boiler water during any given period, say, within a day of 24hours, or within an operating shift for example, is fixed andascertainable. Some salines in the boiler feed are usually desirable. Inanother and prior Patent, No. 1,235,815, I have described the advantageof maintaining certain concentrations of salines in the boiler and inaccessories where hot water is in contact with Iron.

The steamevaporated ,from the boiler water leaves in the boiler thesolids originally contained in the feed water and as a result theconcentration of salines in the boiler increases during operation. Forany given installation, there is a maximum permissible concentration ofsalines in the boiler water, which can be readily ascertained. The highrate of evaporation obtained in boilers of the modern type, wherein theentire liquid contents may be replaced within a short time, introducesnew difliculties in the control of the saline content. The rapidity ofthe concentrating action within the boiler necessitates acorrespondingly high rate of blow- 100 object economically by a methodand means vals to remove a large proportion of the boiler salines andthen to permit the concentrating action to repeat ltself until a portionof the boiler contents is manually discharged. This method of operationis manifestly crude and unsatisfactory, and attempts have been made toblow off the boiler salines with automatic control coordinating the rateof removal of salines in the blow-01f water with the rate of feedingwater to the vboiler. While such coordination is an improvement overthecrude method of manual control,

it involves expensive equipment as well as high cost of maintenance; itis also complicated and for all these reasons not very desirable forpractical purposes. IV hat is required is to hold the concentration ofsalines in the boiler water down belowthe point at' which foaming,priming and other troubles begin.

In the present invention I accomplish this comparatively simple. Idischarge the boiler salines under pressurefrom the boiler justedconstant rate of continuously and at substantially constant rates overrelatively long operating periods without attempting to coordinate themomentary rate .of discharge with temporary variations in the rate offeeding water to the boiler. So doing, I set the discharge for anoperating period at a fixed rate calculated to remove from the boilerthe salines introduced in the feed water during that period and maintainthat rate substantially constant for a relatively long period of time,adjusting the fixed rate of discharge, when required, to

, ,hold the concentration of the boiler salines in the boiler below adesired maximum. Adj usting and fixing the rate of discharge from timeto time is readily and adequately accomplished by increasing ordecreasing the addischarge over and operating period, an eight hourshift for example, in accordance with the 'density of the salinesthemselves as discharged. A ready and adequate means of periodicadjustment of the discharge at fixed rates is provided by putting in thewater discharge line a control tank open to the atmosphere whichreceives discharged salines with release of pressure through a valvecontrolled by a float in the tank, the liquid level in the tank beingThe usual high pres-- It has been common practice to blow down theboiler at inter maintained substantially constant by a controlled outletwhich under a small liquid head in the tank is adjusted to allow aconstant flow of liquid salines from the tank and through the medium ofthe discharge valve with float control maintains a substantiallyconstant saline discharge from the boiler irrespective of changes in theboiler pressure. For heat economy and for regularity of discharge Iplace in the discharge line between the boiler and the discharge linecontrol valve a cooler which advantageously takes the form of a heatinterchanger through which the feed water or part of it is passed on itsway to the boiler. I may also place in the discharge line between thecooler and the saline discharge control valve a thermostatic valveadapted to cut down, or substantially stop, the saline discharge uponundue rise of temperature in the discharge line due to stopping of thefeed water or other cooling medium or due to other and unforeseenemergencies. A valve with automatic control means may also be providedto start or sto discharge line as the ow of feed water starts or stops.I may also place in the discharge line a filter for the purpose ofremoving from the discharge salines any boiler scale or other solidparticles carried thereby.

. In the described procedure as carried out the described means, thesaline content 'of the boiler water, which is of course higher than thatof the feed water, is held within predetermined limits by adjustment ofthe outlet of the control tank. In other words, regulation is effectedafter the cooling of the salines and their release from the boilerpressure. Assuming, for example, that the concentration of salines inthe boiler water has to be heldat a value of 3500 milligrams of totalsolids in solution per .liter of boiler.

water, and assuming that the feed water con tains as an average over aperiod of time 100 milligrams of salines er llter, it is necessary to soadjust the disc arge as to remove an aliquot and sufficient portion ofthe boiler water to take out the salines introduced. Thus in thisexample, the amount of water theoretically required to be dischargedfrom the boiler is one thirty-fifth of the amount of the feed water. Inpractice this result is ob-,-

tained by observing the density of the discharged salines from time totime as by means of an ordinary hydrometer and adjusting the outlet ofthe control tank in accordance with the actual concentration of salinesthe flow through the as reflected in' their density, increasing thefixed rate of discharge if the density increases and decreasing the ratewhen a decrease of density is shown. So doing, the rate of discharge maybe constant over long periods of time. Itmay be necessary to adjust therate not oftener than once during each operating shift.

In the accompanying drawing I havewhich is controlled by a sliding valve21..

shown, more or less diagrammatically,several embodiments of myinvention. In this show- 1ng: 1

Fig. 1 is a view partially in side elevation and partially in crosssection of an assemblage of apparatus for controlling the blowofl" ofboiler salines;

Fig. 2 is a similar view showing an alternative arrangement for removingboiler salines from the boiler;

Fig.3 shows a modified connection between the saline discharge line andthe boiler. As illustrated in Fig. 1, a boiler 10 is provided with adischarge line 11 extending through the top of the boiler casingdownwardly to a point below the low water level in the boiler. Thedischarge line 11, which has a valve. 12 disposed therein, runs to acooler shown as a heat exchanging apparatus 13, wherein the heat of thedischarged boiler salines may be transferred to feed water flowingaround a coil 14 through which the boiler salines pass. The cooledboiler salines flow through a pipe line 15 to a control tank 17. In thedischarge line may be placed a filter 42 and a thermostaticallycontrolled valve 16, which may be so adjusted as to cut off thedischarge of boiler salines when the valve temperatureexceeds apre-determined degree. The control tank 17 is open to the atmosphere.Into this tank the salines are discharged with release of the boilerpressure through a valve 19 which is controlled by a float 18, the tankbeing provided with an outlet pipe 20 communicating with an orfice 20ain the bottom of the tank,

Outlet pipe 20 has a vent 20b. Orifice 20a may be set at a giveneffective area by means of valve 21. With a given height of liquid intank 17 this orifice area is" readily set to give a constant rate offlow from the tank through outlet 20. This constant rate of flow isautomatically maintained and reproduced in the saline discharge line bythe action of float 18 in control of valve 19. Should the discharge ofliquid into tank 17 be greater than the flow through orifice 20a theliquid level wouldrise. Float 18 is arranged to restrict the passagethrough valve 19 in this event, whereupon the liquid level drops. Shouldthe fiow from tank 17 be greater than the discharge into it, float 18drops and opens valve 19 further. Thus the liquid level in tank 17 ismaintained substantially constant and the rate of flow remains fixed.The outlet line 20 may be provided with a valve 22 available forshutting off the discharge of salines entirely, for, with this valveclosed the liquidlevel in tank 17 rises high enough to cause float 18 toentirely close valve 19.- i

Feed water is introduced to the boiler 10 by means of a pump 24 and apipe line 25, and, as shown, runs through the heat exchanger 13 andthence through pipe 26, provided with valve 27, to the boiler. As shown,the feed pump 24 is a steam pump supplied with steam through a steamline 28 which has a connecting line 29 running to the valve 22, thesteam line'28 being provided with valve 31. In this arrangement valve 22is a steam operated valve. In this case the opening and closing of valve22 to start and stop the discharge of boiler salines is automaticallyeffected as steam is turned on or ofi at valve 31 to start and stop thesteam pump 24. It is apparent that other types of connections, based onmechanical, hydraulic or electrical principles, could be employed forthis purpose. Means of such character are well known and it isunnecessary for an understanding of this invention to describe them indetail.

In operation, the discharge of boiler salines is carried on continuouslyand at a substantially constant rate by setting valve 21 to adjust theoutlet from tank 17 at a rate sufficient to maintain the boiler salineconcentration below a desired limit. It is a simple matter to determine,for any installation, the amount of salines which are introduced to theboiler" in any given period of time by the feed of water, even though inmost cases the feed of water to a boiler is variably continuous, beingoften automatically varied to maintain a desired level of water in the20 at a point beyond the prifice 20a, preventsv the water column in pipe20 from exerting a suction afiecting the rate of flow through 1- orifice20a. The .boiler water is normally discharged through the tank 17 in acool condition, which enables the operator to tell at a glance whetherthe boiler is blown 0E properly. Furthermore, he can take a sample fordensity testing without difficulty and should thedensity of the salinesas discharged show a tendency to increase over an operating pe- "riod itis a simple matter to adjust valve 21 accordingly.

The valve 19 is self-cleaning. If a foreign particle enters the valvethe flow becomes reduced, consequently the. float 18 drops, therebyopening the valve further and allowing the particle to be dislodged. Thetotal efi'ective head causing the boiler water to discharge throughorifice 20a in the bottom of tank 17 is only the de th of water in thetank above that orifice. onsequentlythe orifice area is relatively largeand thisminimizes the danger of clogging. The head of Water above theorifice is accurately maintained by float 18 controlling valve 19 and acontinuous discharge at a constantrate is mainv tained automaticallyover any desired period of time. The rate of flowfrom the boiler throughdischarge line 11 is substantially constant irrespective of variation inthe boiler pressure which causes the flow. The thermostatic valve 16,with or without the steam valve 22, acts as a safety devicecutting offthe boiler blow-off when the feed of water is stopped, and thuspreventing undesirable steam flashing in tank 17 and steam hammering inthe blow-ofi' system. lt'substantially prevents heat loss in the blowoff. The automatic control line 29 for valve 22 need not be included,provided the operator closes either one of the valves 12 or'22 at thetime he stops pump 24. However, its inclusionmay be advantageous sinceit serves as an automaticrmeans for stopping the flow of salines whenthe feed of water to the boiler is stopped and for preventing loweringof the water level in the boilerbelow the permissible low water level.

TnFig. 2 ll have shown an alternative arrangement for removing thesalines from the boiler and for cooling and discharging the boilersalines independently of the feed of water to the boiler. In thisarrangement blow-off 11 is provided with an equalizing pipe 32 extendingfrom the top of the boiler to a manually operable blow-down line 33connected into the boiler near the bottom.

The pipe line 11 is disposed at a desired level and will not conduct anundue quantity of water from the boiler. The line 11 is connected to acooler 130: through which the boiler salines pass in a coil 14a, thecooling 7 fluid, which may be make-up water, or feed water, or othersuitable liquid, being introduced .and withdrawn through pipes 23 and30, respectively. From the cooler the discharge line continues in pipe15 running to control tank'17 which functions in a manner similar tothat of control tank 17 in Fig. 1. The discharge line valve 19 heretakes the form of a slide valve controlled by float 18. The outlet fromtank 17 is here shown as a needle valve 21 having a screw handle 21a anda scale 21?), by means of which close adjustment of the outlet valve, isfacilitated. The outlet pipe 20 delivers, as shown, into an openreceptacle leading to a sewer or other place of disposition of thedischarged boilersalines. When desired or required for any ing valves, afilter, suchas filter 42 of Fig. 1,

may be interposed'in the discharge line advantageously between thecooler or'heat interchanger and the control tank, As filtering medium43, quartz, sand, slags, etc. or other suitable material may beemployed. If the Water is strongly alkaline, iron balls may be employedadvantageously. The filter may be cleaned occasionally by backwashingaccording to usual practice, introducing a boiler water is normallycooled before it reaches the filter.

The filter shown in Fig. 3 is positioned ahead'of the heat exchanger andaccordingly it includes means for removing steam which may separate fromthe boiler water by reduction of pressure. The boiler salines aredischarged from the bottom of the boiler reservoir and delivered to thefilter through valved pipe 51, entering near the bottom and flowingupwardly through the filter bed .54 and out at 55. At the top oftheifilter casing, pipe 56 with a float valve is provided for thepurpose of releasing separated steam. A valvedrain pipe 59 is providednear the bottom. 1

While the foregoing description applies more particularly to a steamgenerating plant having but a single boiler, it is apparent that theprinciples of the invention are applicable to installations including anumber of boilers.

Many plants depend upon a single pump to supply several boilers, and theamount of water delivered to each is automatically controlled inaccordance with the duty imposed I upon the boiler. Constant leveldevices, for regulating the amount of water in eachboiler, andthrottling means employed for admitting the water to the boiler, renderthe quantities supplied to each variable over appreciable limits. Inother words, the load carried by each boiler of a set differs from thatcarried by the'others even if all the boilers are connected to the samesteam line.

Each boiler, should, therefore, be provided with a separate dischargeline 11 and an individual controlling device, such as the float valvetank 17 and regulator valve 21. The heat exchanger 13 may be providedwith a plurality. of coils 14, one for each boiler. This arrangementsimplifies control and lessens the cost of the apparatus. A furthersimplification is possible by providing a common heat exchanger andcontrolling device to which each of the individual discharge lines 11 ofeach boiler is connected. In this event the valves 12 in the dischargelines 11 mustbe set to apportion the rate of discharge from each boilerto the common controlling device in accordance with the duty imposedupon each boiler. g

In either case, irrespective of the number l of boilers, the amount ofboiler salines withdrawn may be regulated for each boiler within theoperating range.

From the foregoing it will appear that a simple and economical system isprovided for controlling the concentration of the saline The apglication1s a continuation of application 1927.

What I claim is 1. In controlling the concentration of salines in boilerwater, a simplified method of removing saline matter introduced in thefeed water which consists in discharging boiler salines under pressurefrom the boiler substantially continuously over consecutive operatingperiods at constant ratesfixed for said periods and calculated to removefrom the boiler the salines introduced in the feed water during therespective periods, maintaining the rate for each period constantirrespective of changes in the boiler pressure, releasing the dischargedboiler salines to atmospheric pressure and adjusting the rate of flow ofthe saline discharge at intervals, said adjustment being in'accordancewith observed variations in the density of the discharged salines.

2. In controlling the concentration of salines in boiler water, asimplified method of removing saline matter introduced inthe feed waterwhich consists in discharging boiler salines under pressure from theboiler substantially continuously over consecutive operating periods atconstant rates fixed for said periods and calculated to remove -from theboiler the salines introduced in the feed water during the respectiveperiods, maintaining the rate for each period constant irrespective ofchanges in the boiler pressure, cooling the discharged salines whileunder pressure from the boiler, releasing the cooled salines toatmospheric pressure and adjusterial No. 173,781, filed March 8,

ing the rate of flow of the cooled salines at.

under pressure from a boiler substantially continuously during operationof the boiler, setting the discharge at substantially constant ratesover consecutive operating periods, said constant rates beingirrespective of 3 changes in the boiler pressure and independent oftemporary variations in the rate of water feed, and adjusting the setrate of discharge after consecutive operating periods in directproportion with observed variations in the concentration of the boilersalines discharge-d during said periods.

4. In operating a steam boiler receiving varying amounts of salines inits 'feed water, the process of limiting the accumulation of salines inthe boiler which consists in discharging the boiler salines underpressure substantially continuously during operation of the boiler andat substantially constant rates over consecutive operating periods,

said rates being independent of temporary.

variations in the rate of water feeding and maintained constantirrespective of boiler pressure variation, cooling the discharged boilersalines by heating the feed water therewith and regulating the dischargeby adjusting the rate of flow of the cooled salines after consecutiveoperating periods, said adjustment being in direct proportion withobserved variation in concentration of the boiler salines dischargedduring said periods.

5. In operating a steam boiler receiving varying amounts of salines inits feed water, the process of limiting the accumulation of salines inthe boiler which consists in withdrawing boiler salines under boilerpressure substantially continuously and at substantially constant ratesover consecutive operating periods, maintaining said rates constantirrespective of boiler pressure variation and of temporary variations inthe rates of water feeding, cooling the withdrawn boiler salines byheating the feed water therewith, discharging the cooled salines toatmospheric pressure and controlling the withdrawal of salines byadjusting the rate of How of the cooled. boiler salines afterconsecutive operating periods in accordance with observed variations inconcentration of the boiler salines discharged during said periods.

6. Apparatus for limiting the accumulation of dissolved salines inboiler water which comprises in combination with a steam boiler, a waterdischarge line therefrom, a control tank open to the atmosphere andreceiving boiler salines from the discharge line,

a valve in the discharge line, an adjustable outlet from thecontrol tankand afloat in the control tank connected to the discharge valve, saidfloat being raised and lowered by changes in the level of boiler salinesin the "control tank.

7. Apparatus for limiting the accumula-' tion of dissolved salines inboiler water which comprises in combination with a steam control tankopen to the atmosphere'and receiving boiler salines from the dischargeline, valve means in the discharge line, a vented adjustable outlet fromthe control tank, and means in the control tank operatively connectedwith and adapted to control the discharge valve means so as to maintaina substantially constant level of liquid in the tank.

8. Apparatus for controlling the concentration of dissolved salines inboiler water comprising in combination with a steam boiler a waterdischarge line running therefrom, a heat exchanger in said line adaptedto cool the line by transfer of heat to water going to the boiler, acontrol tank receiving boiler salines from the discharge line, a valvein the discharge line, a vented adjustable outlet from the control tankand means in the control tank operatively connected with and adapted tocontrol the discharge valve so as to maintain a substantially constantlevel of liquid in the tank.

9. Apparatus for controlling and maintaining a saline content in aboiler comprising a boiler, a water discharge line therefrom, a heatexchanger and a filter in said line, a constant level tank receivingwater from the line and provided with a float valved inlet connectedwith the water discharge line, the float being responsive to the levelin the constant level tank, and with an adjustable out let, means forsupplying feed water to the boiler through said heat interchanger, a

valve beyond the outlet and means for closing said valve upon cessationof flow of the feed water.

10. In apparatus for establishing and maintaining a predetermined salineconcentration in a boiler, a boiler, a water discharge line extendingtherefrom, a heat-exchanger in the line, means for supplying the boilerwith feed water through the exchanger, a constant level tank receivingwater from the line, said tank being provided With a floatcontrolledinlet from the discharge line, the float being responsive to the levelin the constant level tank, and'with an adjustable outlet, a valvebeyond the outlet and means for opening and shutting said valvewithflowand cessation of flow of feed Water 11. In apparatus forestablishing and maintaining a predetermined saline concentration in aboiler, a boiler, a water discharge line extending therefrom, aheat-exchanger in the line, means for supplying the boiler with feedwater through the exchanger, said means including a pump, a valve insaid discharge line connected in parallel with starting means for thepump, and a tank. re-. ceiving the discharged boiler water, said tankbeing provided with a float-controlled inlet runmng from the dischargeline, the. float being responsive to the li uid level in the tank, andwith an adjustabe outlet.

12. In apparatus for establishing and maintaining a predetermined salineconcentration in a boiler, a boiler, a water discharge line extendingtherefrom, a heat-exchanger in the line, means for supplying the boilerwith feed water through the exchanger, said means including a steampump, a constant level tank receiving water from the line, said tankbeing provided with a float-controlled inlet running from the dischargeline, the float being responsive to the level in the tank, and with anadjustable outlet, a steam operated valve beyond the outlet and a steampipe connecting said valve and the steam inlet of said pump. I

13. Means for establishing and maintaining a predetermined salineconcentration in a steam boiler which comprises a boiler salinedischarge line extending from the boiler, a heat exchanger in the line,means for supplying the boiler with feed water through the exchanger,means automatically closing the discharge line upon cessation of flow offeed water, a regulating valve in the discharge line beyond the heatexchanger and means associated with the flow of cooled salines forautomatically adjusting the valve to maintain substantially constantrates of discharge.

14. A method of controlling the saline concentration of the water insteam boilers during operation thereof which comprises feed ing salinewater into the boiler, allowing the salines to accumulate to apredetermined concentration in the boiler water, discharging the salinesunder pressure from the boiler in a substantially continuous flow and inrelative volume approximating a fraction of the boiler feed equal to thesaline concentration of the feed water divided by that of the dischargedsalines, maintaining the rate of discharge over an extended period oftime substantially constant irrespective of changes in the boilerpressure and independent of temporary variations in the rate ofboilerfeed and adjusting the rate of discharge at the end of said period toincrease or decrease said rate for a succeeding period in directproportion with observed increase or decrease of the salineconcentration during the preceding period.

15. In maintaining a desired saline content in steam boiler water, amethod of control which comprises removing from the boiler a quantity ofsaline matter substantially equal to that introduced in the feed waterby discharging the salines under pressure continuously during operationof the boiler and at a rate approximating a fraction of the rate offeedequal to the saline concentration of the feed water divided by thesaline concentration desired in the boiler, maintaining the period indirect proportion to observed change in the saline concentration duringthe preceding period.

16. A boiler blow-ofi' control system for removing boiler salines froman operating steam boiler in quantity substantially equal .to the salinematter introduced in the feed water, said system comprising in combination with a boiler, a water discharge line therefrom adapted forcontinuous discharge of salines under pressure during operation of theboiler, means in said discharge line for adjusting the rate of flow ofthe salines through said line and means associated with said adjustingmeans for maintaining said adjusted rate of flow constant irrespectiveof boiler pressure variation.

- 17. A boiler blow-01f control system for removing boiler salines froman operating steam boiler in quantity substantially equal to the salinematter introduced in the feed water, said system comprising incombination with. a boiler, a water discharge line therefrom adapted forcontinuous discharge of salines under pressure during operation of theboiler, a heat exchanger in said line adapted to cool the dischargedsalines by transfer of heat to the feed water, means in said dischargeline beyond the heat exchanger for adjusting the rate of flow of thecooled salines through said line and means associated with saidadjusting means for maintaining said adjusted rate of flow constantirrespective of boiler pressure variation.

18. A boiler blow-ofl control system for removing boiler salines from anoperating steam boiler in quantity substantially equal to the salinematter introduced in the feed water, said system comprising incombination with a boiler, a water dischargev line therefrom adapted forcontinuous discharge of salines under pressure during operation of theboiler, a -cooler in said line, means in said discharge line beyond thecooler .for adjusting the rate of flow of the cooled salines throughsaid line and means associated with said adjusting means ior maintainingsaid adjusted rate of flow constant irrespective of boiler pressurevariation, said two associated means being adapted to release thesalines to atmospheric pressure.

In testimony whereof,

fixed my signature. 7

HEINRICH KRIEGSHEIM.

I have hereunto af-

